This application relates generally to methods, systems, and apparatus for identifying, characterizing, and treating rotors associated with fibrillation. Some methods described herein are suitable for distinguishing between and/or classifying substrate rotors and non-substrate rotors. Substrate rotors may be associated with and/or may significantly influence arrhythmias, while non-substrate rotors may not be strongly associated with arrhythmias. Some embodiments described herein can include treating substrate rotors and/or not treating non-substrate rotors, which can improve cardiac outcomes.
In the last few years, scientific understanding of atrial fibrillation has discovered that the electrical activity in the heart during atrial fibrillation is not complete chaos as once accepted under the Moe model of random wavelets of electrical activity causing atrial fibrillation. There are indeed local organized electrical drivers of atrial fibrillation. Recent research has revealed that electrical patterns in the heart commonly referred to as rotors play an important role in many cases of fibrillation, particularly persistent atrial fibrillation. Currently, surgical systems are available that modify cardiac tissue during treatment using RF energy, cryo, laser, direct current, stem-cells, or drugs. In some situations modifying, ablating, or “burning” a rotor can significantly improve cardiac function.
Known surgical techniques, however, have inconsistent results; ablation of some rotors results in significant changes in heart rhythm, while ablation of other rotors does not have a significant effect. A need therefore exists for methods, systems, and apparatus for identifying and characterizing rotors.